Toenail melanoma is a form of skin cancer that forms underneath the toenail, states DermNet NZ. Melanoma that forms underneath the toenail often appears as a brown or black streak under the nail.
Toenail melanoma is one of many forms of melanoma. Most melanoma appearing underneath the nail unit stems from the surrounding skin, such as the soles of the feet. Toenail melanoma is technically referred to as a variant of acral lentiginous melanoma, reports DermNet NZ. Melanoma can appear anywhere on the human body. Although not always, toenail melanoma is due to skin damage or trauma, and it is not thought to be caused by excessive sun exposure without proper protection, as with most melanoma.
Toenail melanoma often surfaces as a bruise that appears not to heal underneath the nail. There are three forms of melanoma that can form underneath the nail: subungual melanoma, ungual melanoma and periungual melanoma, says DermNet NZ.
Toenail melanoma forms as a dark-colored band that extends the length of the toenail, as stated by WebMD. Over time, this band becomes wider, changes pigmentation, creates a nodule, bleeds, causes thinning of the nail, or causes the entire nail bed to crack. Toenail melanoma is treated by the removal of the infected nail. In some cases, entire tips of toes are amputated to stop the melanoma from spreading further into the body, claims DermNet NZ.